Generic medical instruments in which the movable jaw member can be activated by means of a push-pull element, starting from a rotatable gripping member of the handle, have a variety of uses especially in endoscopic surgery, for instance as punches, scissors, needle holders, grasping instruments, and the like. In these instruments well known in the art, the jaw members that form the tool are as a rule positioned in the longitudinal direction of the instrument shaft, so that with these instruments it is possible to reach only operating areas that are positioned to be directly accessible, essentially in front of the tip of the instrument. However, because many operating areas are not accessible in a straight-line manner, these known instruments are either not at all appropriate for these purposes, or only to a limited extent.
Also known in the art are generic medical instruments in which the jaw members of the tool are turned laterally at an angle to the longitudinal axis of the shaft. Because in these instruments the rotatable jaw member of the tool makes a turning motion relative to the axial motion of the push-pull rod for opening and closing, it is necessary to convert the axial motion of the push-pull rod initiated by the motion of the handle into a rotary motion. For this purpose, based on experience in the art, it is customary to couple the handle and the push-pull rod together by means of a toothed gear. This configuration is relatively simple to produce; however, the transmission of power to the tool does not satisfy all operational requirements.
DE 103 27 655 A1 describes a generic medical instrument that has jaw members turned laterally at an angle to the longitudinal axis of the shaft and in which the motion is converted by means of a transmission lever that, on the one hand, is positioned on the push-pull rod and, on the other hand, is connected with the displaceable jaw member of the tool. This constructive conversion of axial motion into a rotary motion has thoroughly proven itself in the art, but it is expensive to produce.
Consequently it is the aim of the invention to produce a medical instrument of the aforementioned type, in which the conversion of axial motion of the push-pull rod into rotary motion of the displaceable jaw member can be achieved in simple and reliable fashion.